The present invention relates generally to automotive vehicle door latches and more particularly to an electromechanical door latch for an automotive vehicle.
Traditionally, mechanical means have been used to unlatch automotive vehicle doors. It is possible, however, to reduce the effort necessary to unlatch an automotive vehicle door by employing an electromechanical means. A signal from a switch, such as a button on the exterior of the car door, can trigger the electromechanical release of the door latch.
In order to electromechanically trigger the latch release, a switch must be able to short two electrical inputs to ground when depressed. And to satisfy styling and ergonomic requirements, the switch is preferably actuated by a low profile button of adequate size. Current technology uses conductive pills insert molded within the interior of the top of the button to selectively complete a circuit. When the button is pressed downward, the conductive pills contact electrical tracks on the base supporting the button, thus shorting the two inputs to ground. The conductive pills also serve as stops, preventing the button from being further depressed. A problem inherent with this technology is that the pills do not function independently of one another, and thus it is possible to depress the button fully and have only one of the pills make contact with the electrical tracks. For example, because of the button size necessary to fulfill ergonomic requirements, it is common for the button to rock or teeter when an off-center actuation force is applied, thus forcing only one of the pills into contact with the electrical tracks. Because of the unreliable connection inherent in the conductive pill design, it is often necessary to use expensive conducting materials for the pills to ensure better connections, driving the cost of the switch higher. Therefore, it is desirable to have a button that allows both inputs to be shorted to ground when the button is pressed regardless of rocking or teetering, thereby providing a more reliable switching apparatus at a lower cost.
The switching apparatus of the present invention includes an elastomeric button with independently movable electrically conducting spring plates mounted to the button. Each spring plate includes a plurality of cantilever springs. When the button is depressed, the cantilever springs of the spring plates come in contact with electrical tracks, completing a circuit. The completion of the circuit causes a signal to be sent to a vehicle computer, which instructs a motor to release an automotive vehicle door latch.